Easy 10 points question in image on floating and sinking question 4b

On a day when the barometer reads 75.23 cm, a reaction vessel holds 250 ml of ideal gas at 20 celsius. an oil manometer ( ρ= 810 kg/m^3) reads the pressure in the vessel to be 41 cm of oil and below atmospheric pressure. what volume will the gas occupy under s.t.p.?

Acertain radio station broadcasts radio waves that have a wavelength of 298cm what is its broadcast frequency?

If two parallel light rays hit a mirror, they will not be parallel to each other after they reflect.